Place peppers on an aluminum foil-lined baking sheet.
Broil 5 inches from heat about 5 minutes on each side or until blistered.
Place peppers in a zip-top plastic bag; seal and let stand 10 minutes to loosen skins. Peel peppers; remove and discard seeds.
Process peppers and remaining ingredients in a food processor until smooth, stopping to scrape down sides. Store pesto in refrigerator up to 1 week.
Note: Poblano peppers are dark green, tapered chile peppers, about 3 inches wide and 4 to 5 inches long. You can find them in the produce section of your grocery store.